Glow tube



Jan. 27, 1942. 2,270,967

A. E. REEVES GLOW TUBE Filed Feb. 3, 1940 Inn/MITO@x BYIA/J-/f/wd ATTORNEY Patented Jan. 27, 1942 UNITED STATES PATENT OFFICE GLOW TUBE Arthur E. Reeves, Los Angeles, Calif.

Application February 3, 1940, Serial No. 317,159

6 Claims.

This invention relates to Ysound recording; and

particularly by photographic means. This application is a continuation in part of an application entitled Glow tube, filed in the name of Arthur E. Reeves on January 16, 1939, Serial No. 251,155. n

Such systems are in general use. The recording is accomplished by varying the intensity of a beam of actinic radiations, which is directed toward a moving medium carrying a photosensitive surface. Motion picture film is usually employed for this medium, especially where the sound track or record is to be utilized for talking motion pictures.

The source of variableillumination may be any of several types; but this invention deals with glow tubes that havebeen commonly employed for this purpose. Such glow tubes employ a pair of spaced electrodes in a sealed transparent vessel; the potential difference across the electrodes is such as to produce a glow discharge. The intensity is varied by superimposing variations upon the potential difference in accordance with the impulse to be recorded, and the attend- Y ant variations in glow intensity affect the density' of the ultimate photographic image.

While glow tubes of this character have been satisfactorily employed, there is diiculty in securing suiilcient luminosity; and often the glow variations do not accurately follow the impulses.

This lack of iidelity is often due to overloading I of the tube, in an elort to secure adequate illumination.

It is one of the objects of this invention to make it possible to overcome these dilculties.

In using glow tubes/the current glowing between the electrodes produces heating. .It is another object of this invention to make it possible in a simple manner to dissipate the heat.

It is still another object of this invention to arrange the electrodes in such manner as to secure electrode material onto the insulation, with resultant current leakage, is

'I'his invention possesses manyother advantages, and has otherobjects which may be made l more easily apparent from a consideration of 'y posed surfaces.

several embodiments of the invention.y For this purpose there are shown a. few forms in the drawing accompanying and forming part of the present specication. These forms, which illus-- trate the general principles of the invention, will now be described in detail; but it is to be understood that this detailed description is not to be taken in a limiting sense, since the scope of the invention is best dened by the appended claims.

Referring to the drawing:

Figure r1 is a side elevation, partly in section, of a glow tube embodying theinvention; Fig. 2 is an enlarged sectional view, taken along plane 2-2 -of Fig. 1;

Fig. 3 is a view, partly in section, -taken from the left of Fig. 2;

Fig. 4 is a section as seen online 4-4 01E Fig. 2;

Fig. 5 is an isometric view'of one of' the blocks of insulation;

Fig. 6 is a. view similar to Fig. l, but of a modil ed form of the invention; and

Fig. 7 is a detail sectional `view, as seen plane 1'-1 of Fig. 6.

The glow tube illustrated in Figs. 1 to 5, inclusive, includes a sealed transparent envelope I. This envelope may be made from some such material as glass or Pyrex, capable of passing sub-- stantially all wave lengths in the visible spectrum, as well as at least a part of the invisible spectrum.- The glow is intended to be producedover an extensive surface of one of a pair of electrodes 2 and 3, which are shown as closely spaced in thisv instance. These electrodes Aare made from suitable, sheet metal, having similar op- In the present instance these surfaces are parallel planes. Thespacing between the surfaces is such that the usual potential-differences of-several hundred volts across the electrodes may cause the creation of a glow between .the electrodes or over one of the electrode surfaces. A suitable combination 4of ionizlable rare' gases at the usual-pressures, may be employedinthe envelope. y

These-electrodes are supported within the tube or envelope lin any suitable manner. For example, a glass press 4 may be provided extending.

longitudinally of the tube I. In this press are sealed the lead-in conductors 5 and 6 for the A base 'I of insulation material, with suitable prongs 8 and l,

electrodes 2 and 3 respectively.

The electrodes are so arranged that a beam I on Y of actinic rays emerges from the left handy end of the envelope I, in a thin, flat form, and edgewise from between the active electrode surfaces. Thus the glow from the whole space between theseelectrodes is rendered eiective to add to the beam intensity. Provisions are made to limit the glow to the space between the electrodes, as by covering the reverse sides of the electrodes by a layer of insulation.

Preferably in the present instance, these electrode surfaces are covered by the comparatively massive blocks I and II, made of a refractory insulation material, such as lavite. 'I'he opposed faces of these blocks are recessed as indicated at I2, I3, for the reception of the electrodes. The connections I4, I5, forming extensions of the lead-in wires and 8, -are accommodated in appropriate grooves 24 in these blocks. Beads Il, I1 may respectively be placed over the connections I4, .I5 and between the edge of the corresponding block I0, II and the end of the press 4.

Recesses I2, I3, extend from end to end of blocks I0 and II, each recess being defined by side walls I8, I9 (Fig. 5). At one end of the block, the side walls I8, I9 each have portions 20, 2I of increased height, Since blocks I0 and II are identical, when they are assembled with recesses I2 and I3 facing each other, portions 23 and 2| maintain the blocks suiiiciently far apart to provide openings 22 and 23 between the blocks. Thus there is a clear passage from beyond the forward edges to beyond the rearward edges of the electrodes. Since recesses I2, I3 extend from end to end of the blocks, there is similarly a clear space on both ends of the electrodes. By the provision of an open space all around the electrodes, there is no surface upon which material which may sputter oil the electrodes can accumulate. Hence, the possibility of this material forming a conducting bridge with resultant interference in the operation of the tube is practically obviated. Bolts 25, 26 may be used to fasten the assembly together.

In the form of the glow tube shown in Figs. 6 and '7., one of the electrodes is made in two parts so as to form a double sound track record. Thus, one of the electrodes has a pair of electrically separated parts 38, 39. The structure of the glow tube is quite similar to that already. described. However, since there are now three electrodes, the supporting press 4I carries three lead-in wires 42, 43 and 44, which are connected respectively to electrode elements 38, 39 and 40. Likewise, the

tube base 45 is provided with three connecting prongs 46, 41, 48. The supporting blocks 43, 50, serve the same purpose as block I0 and II of the rst form and may be of lavite as before. These blocks 49, 50 are similarly arranged to provide clear spaces at the ends of the electrodes, as clearly shown in Fig. 7.

Thevareas of the spaced active electrode surfaces are made quite substantial. The current density of the electrode surface is therefore low during glow periods, even when a relatively heavy modulating current passes between the surfaces. Accordingly, the variations in glow intensity follow very faithfully the impulses to be recorded,`

irrespective of the intensity of the impulses.

The passage of the glow current between the electrodes 2 and 3 produces a considerable amount of heat. AThe massive blocks I0 and II, being in good heat receiving relation with respect to the electrodes, serve to receive the generate heat and to dissipate it effectively.

What is claimed is:

1. In a glow tube, a pair of thin electrodes having close opposing similar surfaces of substantial area, between'whlch a glow may be produced, a. sealed envelope for the electrodes, massive insulation blocks in heat receiving contact with the reverse sides of the electrodes, said blocks of insulation being so arranged as effectively to absorb and dissipate heat generated in the electrodes, the glow space between the electrodes extending from the front to the rear edges of the opposed areas, said rear edges being unobstructed to provide a clear space between and beyond the electrodes, and conductors respectively for the electrodes, extending in a common direction and attached to the reverse side of said electrodes, each of said insulation blocks being provided with grooves for the accommodation of said conductors.

2. In a glow tube, a pair of thin electrodes having closely spaced opposing similar 'surfaces of substantial area between which a glow may be produced, a sealed envelope for the electrodes, massive insulation blocks in heat receiving contact with the reverse sides of the electrodes, said blocks being capable of absorbing and dissipating heat from the electrodes, and means securing said blocks together in spaced relationship, the glow space between the electrodes extending from the front to the rear edges of the electrodes and from one side to the other of the opposed areas, said rear edges as well as said sides being unobstructed to provide a clear space between and beyond the electrodes.

3. In a glow tube, a pair of thin electrodes having closely spaced opposing similar surfaces of substantial area between which a glow may be produced, a sealed envelope for the electrodes, massive insulation blocks in heat receiving con tact with the reverse sides of the electrodes, and means to secure said blocks together in spaced relationship, the glow space between the electrodes including substantially the entire area of the electrodes, said insulation blocks serving to support the electrodes in spaced relationship and to leave the space between the electrodes substantially open on all sides.

4. In a glow tube, a pair of thin electrodes having closely spaced opposing similar surfaces of substantial area between which a glow may be produced, a sealed envelope for the electrodes, means to support said electrodes in spaced relationship, comprising a block of insulating material on the reverse side of each electrode, each Yblock having raised portions adjacent one end v5. In a glow tube, a pair of thin electrodes having closely spaced opposing similar surfaces of substantial area between which a glow may be produced, a sealed envelope for the electrodes, and means to support said electrodes in spaced relationship, said means including a pair of channel shaped members of insulating material, each member including a web on which an electrode is supported, and flanges longitudinally extending, and means to secure saidmembers together with the flanges in contact whereby the sides of the electrodes are exposed, said flanges being provided with openings substantially coextenslve with the spaces between the forward and rearward edges of the electrodes,

maintaining said blocks in spaced relationship, conductors respectively for the electrodes,v extending along said reverse sides, and insulation material covering the conductors adjacent the insulation blocks, said conductors serving as a support for said electrodes and blocks.

ARTHUR E. REEVES. 

